Two-dimensional finite element simulation of laser rapid prototyping

A method for calculating the distribution of temperature and stress within a plane formed on the powder bed in laser rapid prototyping is proposed. The solidified plane is assumed to be subject to plane-strain deformation, two-dimensional finite element method is employed. In the simulation, finite element meshes are constructed on the powder surface with a constant layer thickness. The area of the laser beam on the powder surface is indicated by five elements and internal heat generation in the elements is modeled as a moving heat source. Latent heat is taken into consideration. Shrinkage due to solidification is shown by the change of the layer thickness. In the elastic finite element simulation, the Young's modulus of the solidified part is expressed as a function of temperature. The powder and molten parts also have the same Poisson's ratio and the small Young's modulus which is 0.5 % of the solid material to simplify the calculation. The heat conduction and the elastic finite element calculations are carried out alternately. The calculated results show the deformation of the solidified plane and the distribution of tensile stress which may cause cracking of the plane while the laser beam travels on a track.